Back in the 80s, before they even had books with the solution (the Internet? What's that?), my Dad quit smoking using a Rubik's Cube.

Getting rid of the nicotine habit takes about 3 weeks to flush it from your system, but smokers are still left with lots of hand-mouth habits that all quitters will tell you is the most difficult thing to overcome. My Dad was a pipe smoker (that was a thing back then), which required a lot of ritualistic behavior, opening the tobacco bag, stuffing the pipe, relighting it with every puff, etc. Lots more than just just pulling out a coffin nail and lighting it.

So to fight the physical habits, he would just pick up his Rubik's Cube, and try to solve it. He didn't just play with it, though, he got analytical about it, writing down moves and steps, and eventually putting together his own cheat guide, before anyone had published one. We didn't think of it at the time, but he could have tightened it up, and probably sold it to a publisher.

I'm any case, it worked. By the time he had solved the Cube, he no longer had the urge to smoke.